A river basin is the area of land where all the water that falls as rain or snow drains into a specific river. This includes the river itself and all its tributaries, which are smaller streams and rivers that flow into it. The boundaries of a river basin are defined by high points in the landscape, known as watersheds, which direct the flow of water toward the river. River basins are important for many reasons. They provide water for drinking, agriculture, and industry, and they support diverse ecosystems. For example, the Amazon River Basin is home to a vast array of wildlife and plants, making it one of the most biodiverse areas on Earth.